<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>
<body>
    <script>
        // str = "?name=zhangsan&age=20&height=178cm";
        // ---->{name:"张三",age:20,height:"178cm"}

        var obj = {name:"张三",age:20,height:"178cm"};
        // str = "?name=zhangsan&age=20&height=178cm";

        // var arr = [];
        var newstr = "";
        for(var key in obj){
            // console.log(key,obj[key]);
            var str = key + "=" + obj[key];
            console.log(str);

            newstr += "&"+str
            // arr.push(str);
        }
        console.log(newstr);
        newstr = newstr.substr(1);
        newstr= "?"+newstr;
        console.log(newstr);
        // var newstr = "?"+arr.join("&");
        // console.log(newstr);
        




    </script>
</body>
</html>